Effect of Purification, Chemical Factor and Shear Stress on Endothelial Differentiation of Human Adipose-Derived Mesenchymal Stem Cells using a Perfusion Bioreactor

The objective of this study was to answer to these principal questions that whether a more homogeneous and purified colony of Human adipose-derived mesenchymal stem cells (hASCs) has significantly higher ability of differentiation in comparison to heterogeneous hASCs colony? And also is the any synergism between chemical and mechanical motivation of hASCs? For this purpose, CD-271+ hASCs were isolated by flow cytometry approach and their differentiation ability toward endothelial cells (ECs) was analyzed after application of mechanical shear stress and chemical growth factor. The results were compared to that of heterogeneous colony of hASCs. Abdominal adipose tissues were isolated from previously informed and consent 25-35 year old healthy women. A perfusion bioreactor was used for application of flow shear stress of magnitude of 4.64 dyne/cm2 purified and nonpurified hASCs which lie on collagen type I coated silicon scaffold. In addition to that, cells were exposed to 50 ng/ml vascular endothelial growth factor (VEGF) for 7 days. Three endothelial specific genes (FLK-1, vWF and VE-cadherin) were selected and their expressions in RNA level were assessed by real time PCR. Real time PCR results demonstrated that generally CD-271+ hASCs have more promising differentiation ability. Also it has been shown that highest expression of ECs specific genes is related to concurrent chemically and mechanically motivated hASCs. In conclusion, mechanical stimulation is at least as important as chemical stimulations and a more homogeneous group of hASCs could be regarded as a more convenient source of cells for vascular tissue engineering applications.